The mechanisms of action of anaphylatoxins and chemotactic factors are not well understood except that they presumably play an active role in the inflammatory process. Our studies will evaluate their role in isolated drug tissue as it relates to mediation of inflammation. We propose to establish an involvement of the anaphylatoxins and chemotactic factors in lung tissue damage and repair. Much of our effort will be spent on collecting detailed chemical and biochemical data from isolated human anaphylatoxins and chemotactic factors. The anaphylatoxins are relatively small proteins derived from serum complement components, however, we have been able to synthesize even smaller peptides which exhibit identical biological activity. The synthetic approach was based on the known sequence of human C3a. These low molecular weight peptides can now be produced in quantities which afford unlimited possibilities for studies on systemic effects in animal models as well as cellular receptor analysis. There is every reason to believe that an equally successful approach will be possible in synthesizing factors with chemotactic activity based on the chemistry of the human serum factors known to promote chemotaxis. Our approach of accumulating the detailed chemistry of these biologically active agents as a prerequisite to understanding the biology, we believe, is a sound approach.